Traditional metal core printed circuit boards (PCBs) are useful in a variety of applications due to their ability to dissipate heat away from electronic components, such as, for example, LEDs. Metal core PCBs are generally formed of a base metal, typically aluminum, copper, or alloys thereof, that acts as a heat sink to dissipate heat away from the integral electronic components of the PCB. Metal cores are often used as an alternative to common FR4 boards (fiberglass/epoxy composition material) or CEM3 circuit boards (polytetrafluoroethylene) because of their superior ability to dissipate heat. Typically, the metal core is applied to a surface of a metal heat sink, a dielectric layer (which is electrically insulating) is then applied to the surface of the metal core, and the electronic components are applied to the dielectric layer.
Conventional metal cores do not provide a great deal of versatility in the design of the metal core layer, as they are typically formed as a solid metal layer. To solve this problem, dielectric paste compositions have been formulated. These pastes may be printed directly onto the substrate in any desired pattern, thereby providing versatility in design and reducing material waste. However, known dielectric pastes do not exhibit durability at elevated humidity levels. The invention provides a dielectric glass composition which may be used as an alternative to the standard metal cores and known dielectric compositions. The inventive compositions exhibit exceptional heat dissipation, electrical performance and adhesion to the underlying substrate, while also maintaining durability at elevated humidity levels. Furthermore, the dielectric glass compositions of the invention allow for the efficient formation of hybrid thick film circuits by printing and firing various thick film materials, such as conductors, resistors, dielectrics, and the like in less manufacturing steps.